BNP leader Nick Griffin looked set to be barred from attending a Buckingham Palace garden party as the political backlash over his controversial invitation grew last night.

Pressure was growing on Richard Barnbrook, the far-right group's London Assembly member who has invited Mr Griffin to accompany him to the event on July 21, to nominate a 'more acceptable guest' or have his invitation withdrawn.

London Mayor Boris Johnson has written to London Assembly chairman Darren Johnson demanding decisive action to prevent any 'potential embarrassment to Her Majesty'.

BNP leader Nick Griffin (right) - who was once convicted for inciting racial hatred - may accompany member Richard Barnbrook to the annual Buckingham Palace garden party hosted by the Queen

Yesterday Darren Johnson said he would, in turn, write to the chief
executive of the Greater London Authority to ask him to ensure Mr
Griffin did not attend.

He said: 'I will ask that unless Mr Barnbrook brings a more acceptable guest the invitation will be rescinded.

Boris Johnson: Trying to stop the BNP 'hijacking' Queen's party

'If there's anything that we can do to stop the
BNP hijacking this event, then we will do.

'Mr Barnbrook has a right to
attend, but we do not want this to become a political event and we will
do anything we can to stop what is proposed.'

Like most public bodies, the London Assembly is given a quota of
tickets for each of the three garden parties held every summer by the
Queen for worthy members of the public.

This year Mr Barnbrook - who became the BNP's highest-ranking
official when he controversially won his seat last May - took up a
ticket and nominated Mr Griffin as his guest.

The revelation sent royal aides into a tail-spin and threatened to hand the far-right group an unrivalled propaganda coup.

It comes at a time when the party is hoping to make a decisive
electoral breakthrough by winning its first-ever seat in the European
Parliament on June 4.

Mr Barnbrook reacted with fury yesterday at moves to remove Mr
Griffin from the guest list and jumped out of his seat during Mayor's
Question Time, shouting: 'This institution is rotten to the core.'

The Mayor replied: 'It is essential to ensure the Queen's garden party is not turned into a political stunt.'

How do you do?The Queen at the annual royal garden party in 2007

In April 1998 - 18 months before he was elected as leader of the
BNP - Cambridge law graduate Mr Griffin was given a nine-month
suspended prison sentence for inciting racial hatred.

Grand event: The Queen hosts a garden party in the grounds of Buckingham Palace last July

Labour MP Jon
Cruddas said: 'It is astonishing that somebody with a criminal
conviction for race crimes could be allowed to attend a garden party at
Buckingham Palace.

'Surely it is possible for someone to have a quiet word with Richard
Barnbrook. There are plenty of other people he could bring.

'He should not be allowed to make political capital of our Royal Family during an election period.'

With European elections ahead shortly, mainstream parties fear the far-right BNP will tap into the mood of public
anger over MPs' expenses and also pick up council seats, which are
contested the same day.

The BNP is threatening to sack a candidate for the European
elections who has been endorsing racist comments on the internet,
embarrassing leaders of the party who are trying to paint themselves as
more moderate. Eddy O'Sullivan, 49, the BNP's organiser in Salford,
joined at least 18 racist Facebook groups including those called 'If
you don't like England then **** off back to where you came from!', and
'No more immigrants, England is full, **** off elsewhere!'